Plain-language answer: A geomagnetic storm is a significant disturbance of Earth’s magnetic environment caused by solar-wind energy coupling into the magnetosphere.
Why operators care
It can disrupt high-latitude and long-path HF propagation, change absorption and MUF, and sometimes create auroral VHF opportunities. Effects vary by latitude and phase.
What to compare on air
Track Kp and storm indices, test several bands and headings, and expect recovery to lag the headline event.
The common mistake
Assuming a storm degrades every path in the same way.
Forecast boundary
Space-weather indices and propagation models describe probabilities and regional conditions. A usable contact still depends on the exact path, time, frequency, antenna pattern, noise, power, and current observations.
